Juno’s View of Jupiter’s Turbulent Poles

byPaul GilsteronMarch 8, 2018

The imagery we’re getting of Jupiter’s polar regions is extraordinary. Juno’s Jovian Infrared Auroral Mapper instrument (JIRAM) works at infrared wavelengths, showing us a vivid picture of a massive central cyclone at the north pole and eight additional cyclones around it. In the image below, we’re looking at colors representing radiant heat, with yellow being thinner clouds at about -13 degrees Celsius, and dark red representing the thickest clouds, at about -118 degrees Celsius. JIRAM can probe down to 70 kilometers below the cloud tops.

Image: This composite image, derived from data collected by the Jovian Infrared Auroral Mapper (JIRAM) instrument aboard NASA’s Juno mission to Jupiter, shows the central cyclone at the planet’s north pole and the eight cyclones that encircle it. Credit: NASA/JPL-Caltech/SwRI/ASI/INAF/JIRAM.

This is hardly the orange, white and saffron belted world we are familiar with from telescope views of the lower latitudes. The scale of these storms is, as you would expect with Jupiter, quite impressive. Alberto Adriani is a Juno co-investigator based at the Institute for Space Astrophysics and Planetology in Rome:

“Prior to Juno we did not know what the weather was like near Jupiter’s poles. Now, we have been able to observe the polar weather up-close every two months. Each one of the northern cyclones is almost as wide as the distance between Naples, Italy and New York City — and the southern ones are even larger than that. They have very violent winds, reaching, in some cases, speeds as great as 350 kph. Finally, and perhaps most remarkably, they are very close together and enduring. There is nothing else like it that we know of in the solar system.”

Adriani’s work on the Jovian polar regions is part of a four-paper set of Juno findings just published in Nature (citations below). We also learn that the planet’s south pole likewise contains a central cyclone, surrounded by five other cyclones with diameters ranging from 5,600 to 7,000 kilometers (the eight northern circumpolar cyclones have diameters between 4,000 and 4,600 kilometers). As Adriani tellingly asks, “…why do they not merge?”

Contrast this situation with Saturn, which houses a single cyclonic vortex at each pole, and it becomes clear that the differences between gas giants can be striking. We also see evidence at Jupiter that the winds dominating its zones and belts run deep, a phenomenon put on display by gravity measurements Juno has collected during its close flybys. “Juno’s measurement of Jupiter’s gravity field indicates a north-south asymmetry, similar to the asymmetry observed in its zones and belts,” said Luciano Iess, Juno co-investigator from Sapienza University of Rome, and lead author on a Nature paper on Jupiter’s gravity field.

That such asymmetries in gravitational measurements exist — and the visible eastward and westward jet streams are likewise shown to be asymmetric — tells us a great deal about how deep these powerful flows extend. This JPL news release explains that the deeper the jets flow, the more massive they are, creating a stronger signal in the gravity field. Juno’s gravity asymmetries thus become a marker for how far down these weather patterns extend.

The massive Jovian weather layer, east-west flows extending to a depth on the order of 3,000 kilometers, contains about one percent of the planet’s mass. Yohai Kaspi, lead author of another of the recent papers in Nature explaining the result, says that seeing the depth of these weather jets and their structure takes us from a two- to a three-dimensional view, adding: “The fact that Jupiter has such a massive region rotating in separate east-west bands is definitely a surprise.” We have much work ahead to determine what drives these jet streams; their gravity signature is entangled with that of Jupiter’s core.

On that score, the surprises seem likely to continue. For a final Juno result now being released suggests that the planet rotates below its massive weather layer as a rigid body.

“This is really an amazing result, and future measurements by Juno will help us understand how the transition works between the weather layer and the rigid body below,” said Tristan Guillot, a Juno co-investigator from the Université Côte d’Azur, Nice, France, and lead author of the paper on Jupiter’s deep interior. “Juno’s discovery has implications for other worlds in our solar system and beyond. Our results imply that the outer differentially-rotating region should be at least three times deeper in Saturn and shallower in massive giant planets and brown dwarf stars.”

Let’s close with a Juno image of Jupiter’s south pole as processed from JunoCam imager data by citizen scientist Gerald Eichstädt.

Image: This image captures the swirling cloud formations around the south pole of Jupiter, looking up toward the equatorial region. NASA’s Juno spacecraft took the color-enhanced image during its eleventh close flyby of the gas giant planet on Feb. 7 at 1011 EST (1411 UTC). At the time, the spacecraft was 120,533 kilometers from the tops of Jupiter’s clouds at 84.9 degrees south latitude. Credit: NASA/JPL-Caltech/SwRI/MSSS/Gerald Eichstadt.

I can’t help but wonder if at least some brown dwarfs may, at close range, look like the infrared north polar view of Jupiter, but have similar hues in *visible* light? Also:

The differences between Jupiter’s and Saturn’s polar cyclonic “scenes” are interesting, but perhaps not surprising. Jupiter is both more massive (roughly 318 Earths versus 95 Earths) and is closer to the Sun (about half a billion miles versus nearly a billion miles) than Saturn, so Jupiter should have a more energetic “gravitational compression internal heat source” as well as receiving more heat from the Sun (which is 1/27th its Earth-distance brightness at Jupiter, and only about 1/400th its Earth-distance intensity out at Saturn). Both of these heat sources would, it would seem, make Jupiter’s poles more meteorologically active than Saturn’s.

The probe launch from Florida in August 2011 was one of the most amazing moments of Becker’s life, she said. “I got to run outside and physically see it fly over my head,” she said. “To physically say goodbye to it and see it launch on its way to Jupiter is so awesome.” This also marked a transitional period. She was no longer an engineer, but a scientist documenting the effects of the Jovian atmosphere on the probe’s instruments, and more. Her work would reveal not just the limits of some of Earth’s best technology, but also help map the planet’s uncharted radiation belts.

Perhaps her most stressful moment after launch occurred while Juno returned to Earth’s orbit for a gravitational assist, as many planetary probes do, to help fling it towards Jupiter in 2013. The team had been hoping to test some of the science instruments when Juno unexpectedly entered safe mode, a near-complete systems shut down after detecting a problem. The issue was soon resolved, but “it was almost the complete opposite of the experience of the beauty of a launch,” she said. “It was a heart-stopping moment because you have no idea if you’re ever going to go or if you’re healthy until you’ve fully come out safe mode.”

I still cannot believe that they actually considered NOT putting a camera on Juno. I thought that kind of lack of foresight disappeared from the space program circa 1962.

Their second biggest mistake was actually considering putting a piece of Galileo Galilei aboard the probe, where it would have eventually been destroyed along with the rest of Juno when it plunges into the Jovian atmosphere. Thankfully they did not go through with that idea.

This is something that needs to be guarded against in future missions when budgets get tight, because it was suggested for Mariner 8 & 9, too! I read (in one of the NASA Mars exploration books) that the Mariner 8 (whose Atlas-Centaur failed) and Mariner 9 spacecraft also could have flown without cameras, as a cost-saving measure. After the 1969 Mariner 6 & 7 flybys made Mars appear to be even more geologically dull and hostile to life (we were *very* lucky that neither they nor Mariner 4 flew by during dust storms–Mariner 9, in Areocentric orbit, was able to study Mars’ moons instead while it waited out the storm!), the value of the upcoming orbiter missions was questioned, but:

Luckily, Mariners 8 and 9 were too far along in development for cancellation to be sensible. But with the smaller NASA budgets of the late 1960s and early 1970s, which the growing Space Shuttle program was already beginning to consume more and more of, other projects were being cancelled, postponed, or scaled back in order to pinch pennies, and:

Many people–amazingly–didn’t consider pictures to be scientifically very useful (even Arthur C. Clarke, in his 1957 book, “The Making of a Moon: The Story of the Earth Satellite Program,” wrote that lunar probe television close-ups of the Moon’s surface would be “Of great curiosity value, though probably of little scientific importance…”), and deletion of Mariner 8’s and 9’s TV cameras was suggested. Fortunately, several of the missions’ scientists pointed out the value of pictures in studies of Areology (Martian geology), meteorology, the morphology and features of Phobos and Deimos, etc., and both probes’ two vidicon TV cameras were retained. (Even Venus–as Mariner 10 showed–proved worthwhile to photograph, after Mariners 2 and 5 flew by it with no cameras at all.)

That is another continual problem with lunar and planetary exploration: People tend to think a few flybys or even an orbiter with lots of pretty pictures equals we fully understand an alien world. That is like having a few flybys of Earth if it were being visited for the first time and then declaring we know everything about that blue and white planet.

We have barely just started understanding our celestial neighborhood. We know about any and all life here beyond Earth past and present even less. We know even less than that about our galaxy.

It boggles my mind that NASA would have sent orbiters to Mars without cameras. Mariner 9 revolutionized our understanding of the Red Planet and its two moons with its cameras and made landing there possible. Charged particle data only excites a very select group of professionals.

Elon Musk knows how to do PR as well as launch rockets and get humanity excited about exploring and colonizing space, something I thought would have been able to sell itself but in the wrong hands I would guess not. I hope other space agencies both commercial and government are taking notes and ignoring the few naysayers who still do not seem to get why Musk lobbed his red sports car into interplanetary space.

I just can’t help but wonder what do these gas giants look like after billions or perhaps trillions of years when they have lost or converted those wild atmospheres into something … other.

Do they leave behind large rocky bodies, small metallic bodies, mix and match of both, what sorts of deposits and mountains are exposed or deposited and when does a surface take form … what sorts of dynamic lumps do they turn into? What becomes of these atmospheres given enough time passage? Are any rocky planets or moons in our solar system remnants of what was once a gas giant? What changes does the core undergo throughout time? … First things first I suppose.

I must laugh at myself considering this, with all the gas giants, near or far from all the stars the imagination is only limited to what I am capable of imagining I suppose. The picture is magnificent in my opinion. A work of art, a thought provoking image, proof of the determination and absolute curiosity and capability of the human. The Universe and its people here on this world continue to just amaze me.

While we do know much more about the Sol system than scientists did before the Space Age, we are only just catching 0n that a few reconnaissance missions hardly tell the whole story. And think how much we don’t know about all those other solar systems for which we barely know they have planets let alone any details. And we know even less about alien life, smart or otherwise.

I am musing about how we might determine if the core is solid or not. I am not being practical but more if it’s even possible given current technology, it’s rookie day here and these are my own ideas, I do not recall reading about this.

Submersibles and shooting anything through Jupiter whether spacecraft or signal is not possible from what I recall. The only thing I can come up with to determine with a test is to set up 2 arrays one on each side of the planet and get them to talk to each other or at least compare results. Talk to each other how? Sonar certainly won’t work, lasers won’t work from what I understand … what permeates that much matter? Gravity is the only thing I know of, but we yet don’t have the ability to send out gravitational waves .. I don’t think (maybe CERN makes small ones, I don’t know)

Ok, give me a go here. You set up 2 laser interferometers (LISA1 and LISA2). One set opposite the other set on both sides of Jupiter. Then you wait, wait for a gravitational wave to come in from an optimal position somewhere in space. LISA1 might show different results than LISA2 and from that extrapolate what occurred while it was passing through Jupiter? Is this plausible at all? Is this a new idea or has it been brought up before? Usually the world has thought of pretty much anything I can come up with so I am a little skeptical that I am being original here.

I am wondering if these features are common around worlds with extended atmospheres, Venus has a double vortex and Saturn has that strange hexagon formation. Perhaps as these worlds get bigger so do the number and strength of these features. Maybe Saturn’s features are the turning point when they turn into Jupiter like features.

In between the central(presumably AT the pole)cyclone and the eight cyclones surrounding it is a poorly defined “octagonal” shaped cloud structure that reminds me of Saturn’s famous polar hexagon. I now wonder if this is the process used to form the hexagon. Were there six cyclones surrounding the polar cyclone in the past, but were unable to remain stable enough to self-perpetuate themselves indefinitely? Will this be the case for the eight Jovian cyclones in the distant future, or will we, in some future era, see an octagon at this region of Jupiter?

There is not correlation between Jupiter’s storms and Jupiter’s aurora because aurora are caused by charged particles in Jupiter’s magnetic field. There might be some charged particles in Earths’ thermosphere or ionosphere where the aurora are which is well above the troposphere. so aurora are considered to be space weather with the Earth and the same with Jupiter.

The solar maximum will affect the weather due to CME and more Sun spots and solar flares which increase cosmic rays and EMR. The CME’s that hit the magnetosphere will certainly increase the aurora activity and electric charge in our atmosphere if more electrons and protons are in the magnetosphere.

The Aurora are the result of charged particles trapped in the magnetic field, electrons and protons which move downward towards the Earth and collide with the atoms in the upper atmosphere where the magnetic field lines move down through the upper atmosphere where they continue into the Earth in the high norther latitudes. Increased aurora activity only the after affect as caused by the result of the solar minimum and maximum. They don’t cause a change in our weather on Earth or Jupiter, but yes there is a correlation between Earth’s weather and it’s aurora.

Also the mainstream idea in planetology or planetary meteorology is that Jupiter’s winds are driven by it’s deep inner heat source, the major cause of Jupiter’s winds and the effects of Sunlight are small compared to the inner source or affect only the top layer of the Jupiter’s atmosphere. Jupiter’s aurora are caused the same way as Earths aurora. Also Jupiter only receives a small fraction of the sunlight as Earth does and due to an inner source, Jupiter clearly emits more heat than it receives from the Sun.

In Centauri Dreams, Paul Gilster looks at peer-reviewed research on deep space exploration, with an eye toward interstellar possibilities. For the last eleven years, this site has coordinated its efforts with the Tau Zero Foundation, and now serves as the Foundation's news forum. In the logo above, the leftmost star is Alpha Centauri, a triple system closer than any other star, and a primary target for early interstellar probes. To its right is Beta Centauri (not a part of the Alpha Centauri system), with Beta, Gamma, Delta and Epsilon Crucis, stars in the Southern Cross, visible at the far right (image: Marco Lorenzi).

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